The novel begins at Devon during the Summer Session of 1942 when Gene and Finny, along with the other members of their class, live lives that have not, as yet, been caught up in World War II. During that summer, the boys discuss the war, but it seems very far away from them:

The class above, seniors, draft-bait, practically soldiers, rushed ahead of us toward the war. They were caught up in accelerated courses and first-aid programs and a physical hardening regimen . . . We were still calmly, numbly reading Virgil and playing tag in the river . . . .

This summer represents the last moments of peace in the boys' lives for many months. When the fall term begins, with its regular classes and regimented schedule, Gene says, "Peace had deserted Devon."

Throughout the following chapters, the war becomes ever-present in the boys' minds as it moves closer to Devon--and to them. Leper enlists, which makes the war a painful reality to all but Finny, who refuses to acknowledge its existence. Seemingly immune to dreary weather and the general depression among the boys, Finny plans and executes a raucous Winter Carnival, complete with cider.

During the festivities, Gene performs amazing and silly physical feats, behaving completely out of character, and it is at this time that for a short while Gene feels that peace has returned to Devon:

It wasn't the cider which made me surpass myself, it was this liberation we had torn from the gray encroachments of 1943, the escape we had concocted, this afternoon of momentary, illusory, special and separate peace.

During the Winter Carnival, the boys are free to be school boys, as they had been during the Summer Session. The world is at war, but for a little while they again feel far removed from it. It is only a momentary peace, however; Leper's telegram arrives, shattering the illusion, bringing the reality of World War II back into their lives.